Almost completely surrounded by Eurasia and North America, the Arctic Ocean is partly covered by sea ice throughout the year[3] (and almost completely in winter). The Arctic Ocean's temperature and salinity vary seasonally as the ice cover melts and freezes;[4] its salinity is the lowest on average of the five major oceans, due to low evaporation, heavy freshwater inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%.[1] The National Snow and Ice Data Center (NSIDC) use satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years.

Geography

The Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2 (5,427,000 sq mi), almost the size of Russia.[5] The coastline is 45,390 km (28,200 mi) long.[5] It is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands.

The two major basins are further subdivided by ridges into the Canada Basin (between Alaska/Canada and the Alpha Ridge), Makarov Basin (between the Alpha and Lomonosov Ridges), Fram Basin (between Lomonosov and Gakkel ridges), and Nansen Basin (Amundsen Basin) (between the Gakkel Ridge and the continental shelf that includes the Franz Josef Land).

Water flow

The Arctic Ocean contains a major choke point in the southern Chukchi Sea,[8] which provides access to the Pacific Ocean through the Bering Strait between Alaska and Eastern Siberia. Subject to ice conditions, the Arctic Ocean provides the shortest marine link between the extremes of eastern and western Russia. There are several floating research stations in the Arctic, operated by the US and Russia.

Ice covers most of the ocean surface year-round, causing subfreezing air temperatures much of the time. The Arctic is a major source of very cold air that moves toward the equator, meeting with warmer air at latitude 60°N and causing rain and snow. This flow is the lower portion of the polar cell, the highest (by latitude) of the three principal circulation cells of the Earth's atmosphere each spanning thirty degrees of latitude. Marine life abounds in open areas, especially the more southerly waters. The ocean's major ports are the cities of Murmansk, Arkhangelsk and Prudhoe Bay.[8]

Shelves

The Arctic Ocean is encompassed by the Arctic shelves, one of which, the Siberian Shelf, is the largest on Earth.

History

For much of European history, the North Polar regions remained largely unexplored and their geography conjectural. Pytheas of Massilia recorded an account of a journey northward in 325 BC, to a land he called "Eschate Thule," where the Sun only set for three hours each day and the water was replaced by a congealed substance "on which one can neither walk nor sail." He was probably describing loose sea ice known today as "growlers", or "bergy bits." His "Thule" may have been Iceland, though Norway is more often suggested.[9]

The few expeditions to penetrate much beyond the Arctic Circle in this era added only small islands, such as Novaya Zemlya (11th century) and Spitsbergen (1596), though since these were often surrounded by pack-ice their northern limits were not so clear. The makers of navigational charts, more conservative than some of the more fanciful cartographers, tended to leave the region blank, with only fragments of known coastline sketched in.

This lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an "Open Polar Sea" was persistent. John Barrow, long time Second Secretary of the British Admiralty, promoted the exploration the region from 1818 to 1845 in search of this.

In the United States in the 1850s and '60s, the explorers Elisha Kane and Isaac Israel Hayes both claimed to have seen part of this elusive body of water. Even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea (1883). Nevertheless, as all the explorers who travelled closer and closer to the pole reported, the polar ice cap is quite thick, and persists year-round.

The temperature of the surface of the Arctic Ocean is fairly constant, near the freezing point of seawater, because Arctic Ocean consist of saltwater temperature must reach -1.8°C before freezing occurs. The density of sea water, in contrast to fresh water, increase as it near the freezing point and thus it tends to sink, it is generally necessary that the upper 100/150 meters of ocean water cools to the freezing point for sea ice to form.[11] In the winter the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic does not experience the extremes of temperature seen on the Antarctic continent.

There is considerable seasonal variation in how much pack ice of the Arctic ice pack covers the Arctic Ocean. Much of the ocean is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April — about 20 to 50 cm (7.9 to 20 in) over the frozen ocean.

Climate has varied significantly in the past; as recently as 55 million years ago, during the Paleocene–Eocene Thermal Maximum the region reached an average annual temperature of 10–20 °C (50–68 °F);[12] the surface waters of the northernmost[13] Arctic ocean warmed, seasonally at least, enough to support tropical lifeforms[14] requiring surface temperatures of over 22 °C (72 °F).[15]

The political dead zone near the center of the sea is also the focus of a mounting dispute between the United States, Russia, Canada, Norway, and Denmark.[16] It is significant for the global energy market because it may hold 25% or more of the world's undiscovered oil and gas resources.[17]

Natural hazards

Ice islands occasionally break away from northern Ellesmere Island, and icebergs are formed from glaciers in western Greenland and extreme northeastern Canada. Permafrost is found on most islands. The ocean is virtually icelocked from October to June, and ships are subject to superstructureicing from October to May.[8] Before the advent of modern icebreakers, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice (although the Baychimo drifted through the Arctic Ocean untended for decades despite these hazards).

Animal and plant life

Endangered marine species include walruses and whales.[8] The area has a fragile ecosystem which is slow to change and slow to recover from disruptions or damage.[8]

The Arctic Ocean has relatively little plant life except for phytoplankton. Phytoplankton are a crucial part of the ocean and there are massive amounts of them in the Arctic. Nutrients from rivers and the currents of the Atlantic and Pacific oceans provide food for the Arctic phytoplankton.[18] During summer, the Sun is out day and night, thus enabling the phytoplankton to photosynthesize for long periods of time and reproduce quickly. However, the reverse is true in winter where they struggle to get enough light to survive.[18]

Environmental concerns

The polar ice pack is thinning, and in many years there will be seasonal hole in the ozone layer.[20] Reduction of the area of Arctic sea ice reduces the planet's average albedo, possibly resulting in global warming in a positive feedback mechanism.[21] Research shows that the Arctic may become ice free for the first time in human history between 2012 and 2040.[22]

Many scientists are presently concerned that warming temperatures in the Arctic may cause large amounts of fresh meltwater to enter the North Atlantic, possibly disrupting global ocean current patterns. Potentially severe changes in the Earth's climate might then ensue.[21]

From Wikitravel

Contents

The edges of the Arctic Ocean are littered with
islands, mostly fragments of the North American, European, and Asian continental masses. Some are inhabited;
others are completely covered in snow and ice and therefore
uninhabitable. Several of the most interesting lie in the border
waters between the Arctic and northern Atlantic Oceans, 60° and
northward toward the Pole.

Understand

The largest number of Arctic islands are parts of the Nunavut and Northwest Territories of Canada, and several are part of
northern Russia; most of these
are barren and uninhabited, and are covered (to the extent that
there's anything to say about them) in their respective countries'
articles.

Greenland – so large
it hardly deserves to be called a mere "island" – lies largely in
the Arctic Circle. Although it is arguably part of continental
North America, it bears cultural and practical similarities to its
smaller neighbors in the Arctic region. Likewise, Iceland barely kisses the
Arctic Circle and has a fairly mild climate, but still has a
sparsely-vegetated landscape and moderate accessibility issues. The
Faroe Islands
are closer to mainland Europe than any of the others (not much
further out to sea than the Shetland Islands), but their small
size leaves them somewhat more isolated. Jan Mayen and Svalbard are quintessentially Arctic – remote
and harsh – but habitable.

Get around

By plane

Although they lie on or near the "great circle" routes taken by
airliners between Europe and North America, the Arctic islands are
generally treated as "fly-over" territories, with fewer stops since
passenger planes gained the ability to cover the distance without
refueling. Because of their historical ties to Europe, they are
easier to get to from there than from Canada or the U.S.

Deutsche Polarflug. [1]. North Pole and
Svalbard sightseeing flights, starting in May 2007, 11-hour
sightseeing flights departing from Germany in an Airbus 330,
cruising over Norway and Svalbard, flying low over special sights,
and getting all the way up to the North Pole. Most passengers
switch during the flight between center-section seats to pairs of
outer-section seats, giving everyone in this class a window or
next-to-window seat for half of the flight; a small number of
tickets are center-section or outer-section only. Informative
in-flight programming. €790-€1190 economy, call for
first-class.

By Tour

Big Five Arctic Tours
[2] - Offers group and individual tours to the Arctic.

Adventure Life VOYAGES[3]. Offering
small-ship expedition to Arctic islands and the North Pole, their
Arctic voyages have been featured in New York Times and USA
Today.

Quark Expeditions[4]. Provides
everything from month-long semi-circumnavigation trips to week-long
explorations of the Arctic, including ice-breakers to reach the
remote North Pole.

The ocean's area is about 14.056 million sq km, which is the smallest of the world's four oceans, and it has 45,389 kilometres (28,203 mi) of coastline. The central surface covered by icepack about 3 metres (9.8 ft) in thickness. The biology there is quite special. Some endangered animals there include walruses, whales and polar bears. The Arctic ocean is melting quicker then usual, as a result of global warming.

The average depth of the Arctic Ocean is 1,038 metres (3,406 ft).[1] The deepest point is in the Eurasian Basin, at 5,450 m (17,881 ft)